Helices in Proteins

Helical conformations in proteins
This page illustrates the 3 most common helical conformations (among secondary structures) found in proteins.

Each of the three examples below is a decapeptide fragment extracted from an actual protein structure in the PDB. They are shown using the same scale, for a better comparison (as a consequence, zoom in the Jmol applets is disabled).

 all set syncMouse on;set syncScript on;sync * on; sync * off; Synchronize the 3 models for rotation with your mouse.  To re-align the 3 models, reload this page.

The alpha helix is by far the most common helix. Note that it is a right-handed helix when formed with the common L-amino acids. (It is left-handed when formed with D-amino acids  .) When viewed from either end, right-handed helices turn clockwise when followed away from you.